FENWICK ISLAND, MARYLAND AND BEYOND: WHO OWNS THE SAND?

Laure Wallace
U.S. Geological Survey
Educational Programs
912 National Center
Reston, VA 22092



Re-printed with liberal changes, from "Who Owns the Sand?", by permission of the University of South Carolina's Center for Science Education.

Level: Grades 7 and above

Estimated time required: One week for research and material preparation. One classroom period for the role-playing activity.

Anticipated Learning Outcomes

Background

Beaches are deposits of unconsolidated sediment that line the shore between the low-water line and the high-water line. Rivers and streams bring sediment to the nearshore environment where it is deposited. Looking at a map of the eastern seaboard of the U.S., large bays are evident. These are drowned river valleys that were eroded during periods of glaciation. When the sea water was locked up in glaciers and sea level was as much as 130 meters lower, the rivers cut down to this lower sea level. With warming climate and subsequent sea level rise, the valleys cut by the Potomac, Susquehanna, and Delaware rivers filled back in. Sediment flowing down these rivers now tend to settle in the upper part of these drowned river valleys and very little reaches the coastal environment. The sand along the Atlantic and Gulf coasts is remnant from the river systems of 20,000+ years ago. The sand is fossil or relict material. If sand is removed from the coast, it is not replaced by the river systems.

The sand in this nearshore environment is affected by wave and wind action. Along the barrier islands of Maryland, strong wave action in the winters can cause beaches to erode. Gentler wave action in the summers can cause the beaches to rebuild. When waves strike the beach at an angle, a current is set up along the shore (longshore current) in which the net movement of water, and of the sand that it carries, is parallel to the coast. This can easily be seen on the map (Fig. 1) by the smooth shoreline of the ocean side of Assateaque and Fenwick Islands. The irregular bay side shoreline of these islands does not have longshore currents. Instead, the irregular shoreline is formed from sand piled up during storm wash-overs and sand blown landward by the wind. During fair weather conditions at Fenwick Island, especially in the summer, there is a slow persistent movement of sand to the north in response to prevailing waves from the southeast. The sand is carried along by the longshore current moving northward. During storms, predominantly in the winter, waves from the northeast prevail and the longshore current (and the sand transport) is southward. On an annual basis, the balance between the northward drift and southward drift results in a net movement of approximately 150,000 cubic meters of sand to the south.

Jetties are rigid shore protection structures that extend from the beach into the surf zone. They are built perpendicular to the beach to trap moving sand. Here they are built in order to maintain the navigation channel; to keep sand out of the channel. These structures, which interrupt not only the flow of sand, but of the longshore current as well, commonly bring about consequences for the adjacent beaches. All flowing water, such as a longshore current, has a carrying capacity for sediment related to its velocity. If sediment is available, as it is along a beach, the current will carry its capacity amount. If sediment is not available, the current will pick up sand from the next available location, to once again fill its carrying capacity. In short, on the downcurrent side of the jetties, the longshore currents will be erosive until all the sediment that has been removed from the current is replaced.

What your students need to figure out is what effect the placement of the jetties at the southern end of Fenwick Island will have on Assateague Island. When the inlet opened to the Isle of Wight Bay during the storm of 1933, the Army Corps of Engineers built jetties to keep the inlet open. The jetties also helped to build an extensive beach for the city which was good for vacationers and storm protection. The results, however, have been catastrophic for Assateague Island. Sand stopped by the Ocean City jetties was not available to replenish sand lost to the longshore current along Assateague, and the island, over the years, has suffered severe erosion and migrated landward. Maps and photographs show extensive evidence of overwash where the dune systems (built by the winds, on sand above sea level) have been depleted. The island, without replenishing sand, is slowly but surely eroding away with the longshore current.

Materials

Procedures

  1. Set up a role-playing activity in which all interested parties can air their concerns to an Arbitration Board.

    Select 2 or 3 students to make up the Arbitration Board. The rest of the students should be divided into the following groups:
  2. Students should read the situation as presented on the student sheet and should be given the pre-1933, 8 1/2 x 11 inch map of the barrier island system. The students' ultimate goal is to decide what will happen if the jetties are built and how they will affect the interests of their group. Allow the students plenty of time to research their individual and group roles. Encourage all students to participate rather than designating just one spokesperson for each group. Information collection can be supported by classroom presentations by the teacher.
  3. On the day of the role play activity, students can be encouraged to dress in the role they are playing.

The teacher may want to prompt ideas with questions (given below). Before the actual role-play, establish ground rules for speaking and participating. Groups will be given five minutes to present their case to the arbitration board, using appropriate diagrams or other presentation media. The arbitration board will then have 10 minutes to make the final decision on whether to permit construction of the jetty. At the end of this process, hand out the map showing the coastline of today and engage further discussion.

Questions to Prompt Ideas for Research and Discussion

What is longshore current?
Waves approaching the coast at an angle set up a sand transporting process along the coast termed the longshore current. The direction and strength of the currents depends on wave heights and direction. Over the coarse of a year there can be a net flow of water and sediment in one direction.

What predominant weather patterns affect the beach?
Seasonal changes in weather patterns change the predominant direction of the wind and subsequently the waves.

Does wind play a part in the movement of sand?
Wind can play a major part in moving sand on the beach face, sand flats and dunes. Storms will throw sand up onto the beach, higher than normal sea level. Once sand is above sea level, then wind can directly transport sand.

Is there movement of sand along the beach?
Sand is moved along the beach both by the longshore current and by wind. Waves can strike the beach at an angle, moving sand up along with it, but the water flows back down the beach at a right angle to the coast line. The effect is a zig-zag pattern, which results in transport of sand along the beach.

Is there a difference in the movement of sand in summer and winter?
During fair-weather conditions along Fenwick Island, especially in the summer, there is a slow persistent movement of sand to the north in response to prevailing waves from the southeast. During storms, predominantly in the winter, waves from the northeast prevail and the longshore current is southward.

Why are beaches built up in the summer?
In the absence of more severe winter storms, waves are usually much gentler in the summer and tend to deposit materials rather than erode.

Why do many beaches show erosion in the winter?
Winter storms with stronger winds and larger waves tend to erode rather than build beaches.

Is there a net movement of sand in the area you are studying?
Yes, about 150,000 cubic meters of sand per year to the south.

Is the area affected by frequent major storms?
Hurricanes are especially destructive when they hit the coast. This area, however, is hit by hurricanes less frequently than any other area of the U.S. Atlantic Coast. Extratropical storms or winter northeasters, however, occur 30 to 40 times each year and many impact this area.

Additional Questions for Research or Discussion

What could a jetty or groin do? How far out would it need to be built?

Does the area need an inlet to the bay? Would you need to consider both the summer and winter environments in making a decision about the inlet?

Would access to the bay help the economy of the area? How many people might visit the area and what is the potential for income to the state?

Is commercial building along the beach good for the local and regional community?

Does commercial building help the tax base of the state?

What information is available about major storm washovers?

Is there a way to balance income from beach development with insurance outlays for national disasters?

Are beach environments really unstable or just in need of managing?

Should any building be on the beach?

What are the effects of washovers on the bay environment?

What is the effect on plant and animal life of human intervention?

Are there any solutions which would satisfy everyone?

How should erosion control measures be paid for?

What laws currently affect development on barrier islands? Are new laws being enacted or suggested? What states are the most aggressive in enacting laws protecting the beach environment from development?



The original version of Who Owns the Sand can be obtained by writing to: USC Center for Science Education, University of South Carolina, Columbia, S.C. 29208.


FENWICK ISLAND, MARYLAND AND BEYOND: WHO OWNS THE SAND?

Student Sheet


Beach systems are dynamic and complex. Human efforts to stabilize an unstable environment will lead to consequences for surrounding areas. Both the positive and the negative consequences need to be considered before any changes are made to that system.


Situation

This is a role-playing activity. The year is 1933. The situation deals with beach processes and erosion affecting Fenwick Island and Assateague Island, Maryland. Although unavailable at that time, you are privileged to have at your disposal the knowledge of coastal processes available in the 1990's. In 1933, Ocean City, Maryland, is just a sleepy little town on the eastern shore of Maryland. It is part of the barrier island system. Although most residents of the town are unaware of it, Ocean City is about to start into a period of major development. Transportation advances, ferry service from Cape Henlopen, Delaware, to Cape May, New Jersey, and the proposed Chesapeake Bay Bridge, will make the eastern shore reachable to people in Washington, D.C., Baltimore, and Philadelphia. This, coupled with a rise in expendable income, will contribute to the rise of a great beach vacation mecca throughout the middle of the century. In this year, 1933, a major storm has hit the coast. In its wake, it has scoured an inlet to the Isle of Wight Bay and has succeeded in breaking the barrier island in two - Fenwick Island to the north and Assateague Island to the south. The city of Ocean City is now on the southernmost tip of Fenwick Island. Assateague Island is in the hands of a few private land owners and a movement is afoot to develop a National Wildlife Refuge and Park and a State Park. Developers and politicians are eyeing Ocean City as prime area for the expanding development of a major resort community. The newly opened inlet to the bay has increased development potential for the bay side. In addition to the developers, Recreational Vehicle Associations and Sport Fishing Associations see this new inlet as a boon to their interests. The U.S. Army Corps of Engineers has decided to build a jetty to keep the inlet open. This move is enthusiastically supported by Ocean City developers and politicians who see this as necessary to their development plans.

Stabilizing the inlet will be accomplished by building jetties at Ocean City Inlet at the southern tip of Fenwick Island. Stabilization will also help to build up the Ocean City beaches and reduce storm damage. The land owners and National and State Park supporters on Assateague are just beginning to question the potential consequences for Assateague Island. An arbitration board is set up to hear the issues presented by the Army Corps of Engineers, the Assateague's Developers and Politicians, and representatives of the Recreational Vehicle and Sport Fishing Associations and landowners, and National and State Park Supporters on Assateaque Island. The question is, "Who Owns the Sand?" The answer is for the arbitration board to decide.

Materials

Procedures

This activity involves role-playing. Each student will be assigned to be a member of a group: Army Corps of Engineers, Ocean City Land Developers and Politicians, Assateague Island Park Advocates and Private Land Owners, the Recreational Vehicle and Sport Fishing Associations, or the Arbitration Board.

Each group must research the role of the people that they represent. Each student is expected to understand the coastal processes that affect the beach of the island they represent. Each group must decide if keeping the Ocean City Inlet open is advantageous to their particular group and must be prepared to defend their view. Each group must write a one-page paper and prepare supporting illustrations that explain their position on the issue to the Arbitration Board.

On the day of the role-play, students should dress in costume befitting their role. Groups will have 5 minutes to present their case to the Arbitration Board, using appropriate diagrams or other presentation media. The Arbitration Board will decide on the fate of the Ocean City Inlet.


Figure 1. Approximate coastline along Maryland's barrier islands prior to 1933. The hurrican of 1933 cut the Ocean City Inlet (marked by dashed lines across the barrier island) and broke the barrier island into two distinct islands, Fenwick and Assateague.


Figure 2. Approximate coastline along Maryland's barrier islands in the 1980s.

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